Cash flow provenance is a modern financial management science, is the investment project in its entire life of the cash outflow and cash inflow of all the amount of money received and paid. Cash flow is the necessary information to evaluate the economic efficiency of the investment program. Specific content includes: (1) cash outflow: cash outflow is all the capital expenditure of the investment project. It includes the following: ① fixed asset investment. Purchase or construction of fixed assets of the capital expenditure. ② investment in current assets. Investment projects require inventory, money funds and accounts receivable and other items occupied by the funds. ③ Operating Costs. Production costs, administrative expenses and selling expenses incurred by the investment project in the course of operation. Usually expressed as the balance of all costs and expenses less depreciation.